1. Field of The Invention
The present invention relates to umbrellas and, more particularly, to umbrellas of the generally large size used outdoors in the patio and garden and commonly referred to as "garden umbrellas".
2. Background Art
The conventional umbrellas and, more particularly, the larger sized patio and garden umbrellas generally are made with a rib support system attached to a means for extending and retracting the ribs to respectively open and close the umbrella. The umbrella has a canopy that is sits on top of the ribs and is attached to the ribs at the rib end tips and at one or more points along the rib length. One problem with umbrellas is that the wind can lift the underside of the canopy and force it into an inside out configuration, often destroying the canopy and the rib support structure. The wind causes flexing of the ribs and mechanical stress thereto, which may result in bending and snapping of the ribs and rib support system.
To overcome the problems of wind caused upon the umbrella and to release the air pressure from below the conventional umbrellas, various forms of holes, openings and vents have been provided in the umbrella cover material. One type of wind vent umbrella is disclosed by John David Farley in U.S. Pat. No. 3,456,661 wherein the normal umbrella covering is open at the top central portion of the umbrella and a top canopy tier is mounted above the opening to provide vents for the air rising from below the canopy. The top canopy tier is required to cover the opening and prevent the rain from passing down through the vents and into the central umbrella covering and onto the umbrella user. In this type of umbrella, the partial umbrella covering, with its central opening, may result in a less stable and less rigid umbrella structure due to the frame support ribs being only partially tied together and covered by the main umbrella covering.
In U.S. Pat. No. 5,226,438 issued on Jul. 13, 1997 to Emanuel Dubinsky, the inventor herein, there is provided a garden umbrella having both a top canopy and a lining attached to the underside of the umbrella ribs, including the stretcher rib structure at the central portion of the umbrella, for deflecting wind and reducing the lift effect of wind against the bottom of the umbrella.